Your furnace is a key part of your home. Without one, you wouldn’t be able to keep warm during cold weather. Yet furnaces can have some problems that are more common than others.
Let’s review these issues and about what they might cost to fix so you know before you call an HVAC technician. Some of the most common furnace repair problems include:
- Furnace won’t turn on
- Furnace doesn’t stay lit
- Furnace won’t blow hot air
- Furnace won’t turn off
1. Furnace Won’t Turn On
There are a few reasons why your furnace won’t turn on, so make sure to check all of them.
- Is your thermostat set right? Make sure it’s set to “heat,” “auto” and that your desired temperature is higher than the room’s current temperature. If you use a programmable thermostat, make sure it has fresh batteries.
- Is the circuit breaker tripped? Your furnace can’t operate if it doesn’t have power. Reset the switch if it’s facing the outside of the electrical panel.
- Is the furnace switch off? Your furnace has a power switch found on or near it. Since this switch looks like a light switch, it’s easy to accidentally turn it off. If it was off, it might take your furnace a few minutes to turn on.
- Is the air filter clean? A dirty air filter can cause a lot of issues for your furnace. Get a new one if you can’t see light through it.
Estimated Repair Cost
This issue can be complicated, so the estimated cost to repair it varies according to what’s wrong.
2. Furnace Won’t Stay Lit
Your furnace uses a certain sequence when it begins heating your home.
- Your thermostat notices the temperature has fallen and tells your furnace to turn on.
- The draft inducer fan activates to pull in fresh air for combustion.
- The gas valve unlocks for the burners, which are lit electronically.
- The flame sensor tells your furnace the burners have been lit.
If something is off during the sequence, your furnace will shut off as a safety precaution.
A couple of possible causes for this issue include:
- Dirty or malfunctioning flame sensor. If the sensor doesn’t detect a flame, it will turn off your furnace to keep natural gas from spilling into your home. The ignition process corrodes flame sensors as time passes. While cleaning during annual furnace maintenance can help, yours may ultimately need to be taken out and changed.
- Bad limit switch. This safety feature will shut off your furnace if it senses backdrafting. Backdrafting is dangerous, because carbon monoxide and natural gas can leak into your home. These switches can fail due to age, damage or dust accumulation.
- Old thermostat. If your thermostat isn’t working properly, your furnace won’t be able to run.
- Dirty air filter. A dirty air filter can restrict airflow and cause your furnace to shut off to avoid overheating. Make sure to change yours every 30 to 90 days, or anytime you can’t see light through it.
Estimated Repair Cost
These costs are estimates, so it’s important to note yours may fluctuate based on your furnace’s brand and model.
- Flame sensor: $350–$500
- Limit switch: $150–$300
- Thermostat: $150–$350
- Furnace filter: $10-$30
3. Furnace Won’t Blow Hot Air
In many cases, this problem is tied to a wrong thermostat setting or a dirty air filter that’s restricting airflow. Follow the steps above to resolve the problem.
4. Furnace Won’t Turn Off
If it’s very chilly outside or you like your home to be warm, your furnace may be working for a long time.
If this isn’t what's happening, make sure your thermostat is set correctly and working properly. If your fan setting is at “on,” the blower motor will be running even when the furnace isn’t, so it’ll seem like your furnace is on all the time.
Alternatively, there might be an issue with the blower motor or your ductwork may be leaking air, forcing your furnace to run constantly to make up for the air loss.
Estimated Repair Cost
These costs are approximations, so it’s necessary to note yours may be different based on your furnace’s brand and model.
- New blower motor: $250–$800
- Seal ductwork: varies based on square footage
Service Max Heating & Air Conditioning Can Solve Your Furnace Issues Quickly and Affordably
Furnace issues can be a costly headache, but not when you work with Service Max Heating & Air Conditioning. We’ve been delivering the quality, affordable furnace repair Arlington homeowners have trusted since 2012. Call us at 360-255-5857 to receive your free estimate today.